1. Field of the Invention
The present invention relates to a display device, and more particularly, to a pixel cell in a display device and a method for driving the same.
2. Discussion of the Related Art
Recently, various flat panel displays having relatively lighter and less spacious than cathode ray tubes (CRT) have been developed. Examples of such flat panel displays include a liquid crystal display (LCD) device, a field emission display (FED), a plasma display panel (PDP), and a light emitting display (LED).
In particular, the LCD device includes a thin film transistor substrate, a color filter substrate, and a liquid crystal layer. The thin film transistor substrate includes a plurality of liquid crystal cells arranged in respective regions defined by a plurality of data lines and a plurality of gate lines. A plurality of thin film transistors serving as switching elements are formed in the respective liquid crystal cells. The color filter substrate includes a color filter layer. Then, the liquid crystal layer is formed between the thin film transistor substrate and the color filter substrate.
The LCD device displays color images using light transmitted through the thin film transistor substrate and the color filter substrate. In this respect, a color realization ratio of the LCD device may be lowered due to the characteristics of color filter. To solve the problem of the low color realization ratio of the LCD device, a field sequential color (hereinafter referred to as an FSC) LCD device has been proposed.
FIG. 1 illustrates an operation of a FSC LCD device according to the related art. As shown in FIG. 1, in the related art FSC LCD device, one frame period, or frame, is divided into three sub frames by time division. Red(R), green(G) and blue(B) colors are mixed in each of the sub frames to display color images. For example, when one frame of the related art FSC LCD device is time-divided into the three sub frames, red(R) light of the first sub frame, green(G) light of the second sub frame, and blue(B) light of the third sub frame are color-mixed at a predetermined ratio to display color images.
With the recent trend of large-size display devices, the number of gate lines increases. Accordingly, a driving time for each gate line decreases. Specifically, the display device necessarily drives all gate lines during a preset time period during one frame. As the number of gate lines increases, a scan time for each gate line decreases. Thus, a turn-on time of a thin film transistor connected to each gate line decreases in accordance with the decrease in the scan time of the gate lines.
Due to the short scan time, the related art FSC LCD device can hardly charge a sufficient voltage at each gate line. To solve this problem, the size of the thin film transistor has been increased. However, design rules restrict the size of the thin film transistor.